This invention generally relates to data support identifying systems, particularly to an improved method of identifying data supports, a device for performing the method and a data support suitable for use in the method.
It has already been proposed to use characteristic individual features of a data support for deriving a random information, by detecting the characteristic individual features along a linear track on the substrate of the data support. The random information may be generated by detecting the physical properties of the base material of the data support. These physical properties being different from one data support to another, the information detected along a linear track will be different from one data support to another. In order to precisely follow the linear track, lateral abutment or automatic centering systems for centering a magnetic reading head on a magnetic reading track by markings on the data support may be provided.
Upon detection of the physical properties of the individual data support for deriving the corresponding random information, detecting errors may result from an expansion of the data support by humidity or temperature changes, leading to the data support being refused upon determination as to authenticity. This is clearly undesirable.